JPS62250130A - Tension controlling method for metallic strip passage device - Google Patents

Abstract

PURPOSE:To decrease tension fluctuation and positional fluctuation of a dancer roll by combining the driving adjustment of the dancer roll and the speed adjustment of a bridle roll to correct strip tension to a set value. CONSTITUTION:The position of a tension detecting roll 5 provided before or behind the dancer roll 2 is detected by a tension detector 6 and the signal 12 thereof is applied to a tension control device 11. The device 11 determines the deviation between the signal 12 and a set tension signal 13 and applies the differential signal 14 to a dancer roll current control device 15 and a bridle roll speed control device 16. The current to be applied to a motor 10 for vertically driving the dancer roll is thereby controlled. The position of the dancer roll 2 is detected by a position detector 3 and the signal 18 thereof is applied to a dancer roll position control device 19. The device 19 determines the deviation between the signal 18 and the set signal 17 and applies a differential signal 20 to a bridle roll speed control device 23 which is turn controls the rotating speed of a bridle roll driving motor 9. The tension of the metallic strip 8 is thereby controlled to the set value.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for controlling the tension of a metal strip threading machine, and in particular, to a tension control method for a metal strip threading machine in which a dancer roll is installed before or after a bridle roll. The present invention relates to a tension control method for reducing tension fluctuations and dancer roll position fluctuations.

[Conventional technology]

In passing the strip, for example, when passing the strip through a continuous processing line such as a continuous annealing furnace, it is necessary to prevent surface flaws, heat buckling, walking, or plate breakage9, etc.

It is necessary to suppress tension fluctuations in the strip.

In the conventional method for suppressing tension fluctuations, tension fluctuations are suppressed by feeding back a tension signal from a strip tension detection device to a power control system that controls tension in a dancer roll.

In addition, the dancer roll position changed to suppress tension fluctuation is controlled by feeding back the position signal to the speed control system of the bridle roll to control tension fluctuation suppression due to dancer roll position fluctuation (for example,
(Refer to Japanese Patent Application Laid-Open No. 52-71320).

[Problem that the invention seeks to solve]

However, in this conventional method, there is hysteresis in the movement of the dancer roll (that is, the amount of current required to maintain a predetermined tension varies depending on the direction of movement of the dancer roll), so the movement of the dancer roll is However, there was a problem in that it could actually induce tension fluctuations. For this reason, especially.

When it is necessary to suppress tension fluctuations to a small level, this conventional method of suppressing tension fluctuations cannot be applied.

The present invention provides a metal strip threading device in which a dancer roll is installed before or after a bridle roll.
The purpose is to perform control to minimize the movement of the rolls and to reduce tension fluctuations in the strip and position fluctuations of the dancer rolls.

(c) Means for Solving Problems] In order to achieve the above object, the present invention provides a metal strip threading device in which a dancer roll is provided before or after the bridle roll; 1- Input the lip tension detection value to the tension control device of the dancer roll, compare it with the tension setting value, and use the signal corresponding to the difference as the tension control signal to drive the dancer roll! The bridle is outputted to the vlJ current control device to drive the dancer roll in the direction where the error becomes zero; the dancer roll position control output, the bridle roll speed detection value, and the bridle roll speed set value are input to control the bridle roll speed. A tension control signal from the dancer roll tension control device is input to a roll speed control device to control the bridle roll speed in a direction in which the error becomes zero.

[Effect]

According to this, when the tension detection value deviates from the tension setting value, the dancer roll is driven in a direction to correct it, that is, in a direction to make the deviation zero, and the bridle roll speed is changed. That is, the strip tension is corrected to the tension setting value in both the dancer roll driving force adjustment and the bridle roll speed adjustment. This results in a reduction in the dancer roll drive force and travel distance to compensate for tension deviations, resulting in less dancer roll hysteresis.

Because of the high inertia of the dancer roll and its associated drive system, small deviations will substantially compensate for tension deviations by adjusting the bridle roll speed. That is, small tension fluctuations are absorbed by the bridle roll speed adjustment, and large tension fluctuations bring about the dancer roll driving force adjustment.

Movement of the dancer roll is therefore minimized. Therefore, the conventional tension control using only the dancer rolls eliminates the problem that the movement of the dancer rolls itself induces tension fluctuations.

Tension fluctuations are reduced. This makes the strip threading highly stable, reduces the occurrence of surface flaws and heat buckles, and eliminates the occurrence of walks.

〔Example〕

FIG. 1 shows a metal strip threading apparatus embodying one embodiment of the present invention. The metal strip 8 leads to the bridle roll 1 from the left in FIG.

The 6 bridle rolls L are rotated by a motor 9, and are rotated approximately half a circle to reach the dancer roll 2, approximately half a circle to reach the tension detection roll 5, and approximately half a circle to reach the continuous annealing furnace 7.
The metal strip 8 is rotated in the direction in which it is delivered to the dancer roll 2. Dancer roll 2 is roller 26,2
It is suspended by one end of a wire 28 which is stretched over the wire 7. A counterweight 4 is suspended from the other end of the wire 28. The roller 27 is rotationally driven by a motor lO, and the dancer
Roll 2 moves upward or downward.

A dancer roll current control device, which is a servo driver, energizes the motor 1O and controls the motor 1 according to the polarity of the energized current.
0 rotates forward or backward, and the rotational torque of the motor 10 is proportional to the absolute value of the energized current.

The tension detector 6 detects the position of the tension detection roll 5, converts this into a tension value, and provides a signal indicating the tension value, that is, a tension detection signal 12, to the tension control device 11. The tension control device 11 generates a difference signal 1 indicating the deviation (positive, negative) of the tension detection signal 12 with respect to the set tension signal 13 indicating the set tension value.
4 to the dancer roll current control device 15 and the bridle roll speed control device 23. The dancer roll current control device 15 energizes the motor 10 with a current corresponding to a signal obtained by subtracting the difference signal 14 from the set tension signal 13 .

That is, the motor current is controlled so that the motor current feedback signal 16 becomes equal to the subtracted signal.

The position of the dancer roll 2 is detected by a position detector 3, and a position detection signal 18 indicating the detected position is given to a dancer roll position control device 19. The position control device 19 provides a position difference signal 20 indicating the deviation (positive, negative) of the position detection signal 18 with respect to the position setting (+'W number 17) indicating the set position to the bridle roll speed control device 23.Bridle roll speed detection The device 25 provides a speed detection signal -22 indicating the rotational speed of the motor 9 to the bridle roll speed control device 23.

The bridle roll speed control device 23 outputs a speed setting signal 2.
The signal obtained by subtracting the position difference signal 20 from the sum of 1 and the difference signal 14 is set as a 1'' target value (speed instruction value), and the motor current 24 is controlled so that the speed detection signal 22 becomes this target value to drive the motor 9. accelerate or decelerate.

With the above configuration, the tension detection signal 12 becomes the set tension signal 1.
When it becomes larger than 3, the difference signal 14 is positive and its absolute value becomes large, the current flowing through the five dancer roll drive motor 10 becomes small, and the torque that pulls the dancer roll 2 upward becomes small. That is, the tension in the metal strip 8 is reduced. On the other hand, the target value increases in the bridle roll speed control device F123, the rotational speed of the bridle roll drive motor 9 increases, and the tension of the metal strip 8 decreases. When the tension detection signal 12 becomes smaller than the set tension signal 13, the difference signal 14 is negative and its absolute value becomes large, the current flowing to the motor IO becomes large, and the torque that pulls the dancer roll 2 upward becomes large. Become. That is, the tension in the metal strip 8 increases. On the other hand, the target value becomes smaller in the bridle roll speed control table [23].

The rotational speed of the motor 9 decreases and the tension in the metal strip 8 increases.

Through such an operation, the tension of the metal strip 8 is controlled to a tension determined by the set tension signal 13.

In this way, the pulling torque control of the dancer roll 2 and the speed control of the bridle roll 1 are performed so that the difference signal 14, that is, the tension deviation, is zero (I tension control by speed control of the bridle roll I). When a tension deviation occurs, the compensation operation to make it zero becomes faster, and the amount of change in the dancer roll driving force and movement llt for compensation becomes smaller, and this causes the change in the dancer roll 2. This will reduce hysteresis.

In addition, due to the responsiveness of tension control by the dancer roll 2,
Since the responsiveness of the speed control of the bridle roll 1 is high, when the tension deviation (difference (No. 3 14) is small), the tension control effect due to the speed control of the bridle roll l is achieved before the tension control by the dancer roll 2 becomes effective. appears, and the difference signal 14 becomes zero.

In effect, the tension control by the J-dancer roll 2 has no effect. That is, small tension fluctuations are absorbed by controlling the speed of the bridle roll 1, and the movement of the dancer roll 2 is not controlled.

If there is no movement of the dancer roll 2, there will be almost no large tension fluctuations, and the threading of the strip 8 will be extremely stable.

FIG. 2 shows an example of test results showing the control effect obtained by applying the method of the present invention.

In this test, a strip having a thickness of 0.6 mm and a length of 200 mm per plate was passed through a continuous annealing furnace 7 as shown in FIG. 1 at a target threading speed of 200 m/min.

In FIG. 2, A on the left is a graph showing the strip tension and dancer roll position when conventional tension control is used, and 8 on the right is a graph showing the strip tension and dancer roll position when the present invention is implemented as described above. It is a graph showing the position. I is the dancer roll position! 1 indicates the tension of the metal strip 8 in the continuous annealing furnace 7, and ▪ indicates the tension of the dancer roll 2. Comparing A (conventional) and No. 13 (present invention), it can be seen that according to the present invention, the change in strip tension: 'P)'' is reduced, and the positional fluctuation of the dancer roll is also reduced.

〔Effect of the invention〕

As described above, in the method of the present invention, the position of the dancer roll is almost constant with almost no fluctuation, and the tension is extremely less fluctuated, so that the tension can be controlled extremely well. Dancer roll movement is kept to a minimum. In other words, all small tension fluctuations are absorbed by the tension control by controlling the speed of the bridle roll, and only when a large tension fluctuation occurs, the tension control system by current control of the dancer roll is activated, causing the dancer roll to move. Therefore, the movement of the dancer roll itself does not induce tension fluctuations, which is a disadvantage of tension control using only dancer rolls, and it is possible to minimize tension fluctuations in tension control of metal strip threading equipment. can.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a block diagram showing the configuration of a metal strip threading device that implements one embodiment of the present invention, and Fig. 2 shows test results B obtained by implementing the present invention using a conventional method. This is a graph shown together with 8. l Nibridle roll 2; Dancer roll 3: Detector at dancer roll position 4: Counterweight 5: Tension detection roll 6: Tension detector 7: Continuous annealing furnace 8: Metal strip 9 Nibridle roll drive motor lO: Dancer roll Vertical drive motor IN tension control device 12: Tension detection signal 13: Setting tension signal 14: Difference signal 15; Dancer roll current control device 16: Motor current feedback signal 17: Position setting signal 18: Position detection signal 19; Dancer roll position control Device 20: Position difference signal 21: Speed setting signal 22: Speed detection signal 23 Nibride roll speed control device 24: Motor current 25 Nibride roll speed detector 25.27: Roller 28: Wire Patent applicant Nippon Steel Corporation Company representative patent attorney Shinyu Minamino and 1 other famous figure 1

Claims (1)

[Claims] (1) In a metal strip threading device with a dancer roll installed before or after the bridle roll: input the detected strip tension value before or after the dancer roll to the dancer roll tension control device and compare it with the tension setting value, A signal corresponding to the difference is output as a tension control signal to the dancer roll drive current control device to drive the dancer roll in a direction where the error becomes zero; dancer roll position control output, bridle roll speed detection value, and bridle roll speed setting A tension control signal from the dancer roll tension control device is input to a bridle roll speed control device in which the value is input and the bridle roll speed is controlled, and the bridle roll speed is controlled in a direction in which the error becomes zero; Tension control method for plate device.